title: Genetic and environmental contributions to regional cortical surface area in humans: a magnetic resonance imaging twin study.
abstract: Cortical surface area measures appear to be functionally relevant and distinct in etiology, development, and behavioral correlates compared with other size characteristics, such as cortical thickness. Little is known about genetic and environmental influences on individual differences in regional surface area in humans. Using a large sample of adult twins, we determined relative contributions of genes and environment on variations in regional cortical surface area as measured by magnetic resonance imaging before and after adjustment for genetic and environmental influences shared with total cortical surface area. We found high heritability for total surface area and, before adjustment, moderate heritability for regional surface areas. Compared with other lobes, heritability was higher for frontal lobe and lower for medial temporal lobe. After adjustment for total surface area, regionally specific genetic influences were substantially reduced, although still significant in most regions. Unlike other lobes, left frontal heritability remained high after adjustment. Thus, global and regionally specific genetic factors both influence cortical surface areas. These findings are broadly consistent with results from animal studies regarding the evolution and development of cortical patterning and may guide future research into specific environmental and genetic determinants of variation among humans in the surface area of particular regions.
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA. lteyler@ucsd.edu
authors.forename: Lisa T
authors.initials: LT
authors.lastname: Eyler
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Prom-Wormley
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Panizzon
authors.forename: Allison R
authors.initials: AR
authors.lastname: Kaup
authors.forename: Christine
authors.initials: C
authors.lastname: Fennema-Notestine
authors.forename: Michael C
authors.initials: MC
authors.lastname: Neale
authors.forename: Terry L
authors.initials: TL
authors.lastname: Jernigan
authors.forename: Bruce
authors.initials: B
authors.lastname: Fischl
authors.forename: Carol E
authors.initials: CE
authors.lastname: Franz
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lyons
authors.forename: Michael
authors.initials: M
authors.lastname: Grant
authors.forename: Allison
authors.initials: A
authors.lastname: Stevens
authors.forename: Jennifer
authors.initials: J
authors.lastname: Pacheco
authors.forename: Michele E
authors.initials: ME
authors.lastname: Perry
authors.forename: J Eric
authors.initials: JE
authors.lastname: Schmitt
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Seidman
authors.forename: Heidi W
authors.initials: HW
authors.lastname: Thermenos
authors.forename: Ming T
authors.initials: MT
authors.lastname: Tsuang
authors.forename: Chi-Hua
authors.initials: CH
authors.lastname: Chen
authors.forename: Wesley K
authors.initials: WK
authors.lastname: Thompson
authors.forename: Amy
authors.initials: A
authors.lastname: Jak
authors.forename: Anders M
authors.initials: AM
authors.lastname: Dale
authors.forename: William S
authors.initials: WS
authors.lastname: Kremen
mesh_terms: D000818:Animals; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019655:Quantitative Trait, Heritable; D012931:Social Environment